Replies

1. 
   peakbagger | Dec 15, 2004 06:51am | #1

   Helps it lay flat if the wall is not perfect.

2. 
   RW | Dec 15, 2004 07:35am | #2

   Its called a relief cut, and yes, what Jim said. Some argue that it adds stability. I think that's bunk if you look at how wood moves, but hey, to each their own. If your walls arent nice and even, and you don't want to relief cut, could you find / make a backmold that would make you happy? I've seen it in older houses, I've used it, I can really only think of one time I saw it in what I'd call an A&C inspired trim setup, and it was, in keeping with the style, pretty basic there. But its a heck of a lot easier to scribe than a 5" wide case. Ditto on your base - cap mold?

    

   "If you pick up a starving dog and make him prosperous, he will not bite you. This is the principal difference between a dog and a man." - Mark Twain

3. 
   HeavyDuty | Dec 15, 2004 07:39am | #3

   Make sure you don't plough all the way to the ends that are going to show.

1. 
   hyena | Dec 15, 2004 08:00am | #4

   On the doors I just hung, (pre-hung), the jambs , which are solid 3/4" thick oak, the manufacturer put three saw cuts about 1/8" deep on the back side, so I'm guessing those are for stability? 

   Some milled base I've used has a wide reccessed area on the back, so I can seewhere that could bridge uneven spots.

   Since this project is Arts and Crafts, it is just s4, so I was planning on buying 3/4" quartersawn oak from the saw mill I buy from. Wood is dried nice and they put a real nice finish plane on it, hardly needs any sanding.

   Was just wondering if I should put any cuts on the bacside and if a certain depth or shape would be more preferrable?

    

   Thanks

    

1. 
   Ragnar17 | Dec 15, 2004 09:03am | #5

   It sounds like you're using some nice, high-quality finish trim, so I think cutting multiple kerfs on the back for reasons of dimensional stability would be unnecessary.  If you were using flat-sawn #2 pine or something, some kerfs would be a good idea.

   Most of the old work I've seen (1900-1920) is simple S4S.  Sometimes, if the trim is profiled, there will be a large relief cut into the back of it, about an 1/8" deep (imagine making multiple passes with a dado blade so that only about a 1/2" or so on each edge remains).  This relief allows the trim to "bridge" over any inconsistencies in the wall.  I don't think it was intended to provide dimensional stability.

    

    

1. 
   HeavyDuty | Dec 15, 2004 09:14am | #7

   Hey Ragnar, I typed too slow and you beat me.

   Long time no see, how's it going?

1. 
   Ragnar17 | Dec 15, 2004 09:18am | #8

   Hi Tom,

   Good to "see" you, too.  I've been doing well.  I have an 18-month old boy now, so I haven't had as much time to screw around on the computer as before!

   Guess what his favorite word is?  "Saw!"  :)

2. 
   HeavyDuty | Dec 15, 2004 09:43am | #9

   Heeeey congrats. 18 month old, that's a handful. They are always a joy.

   "Saw!"?

   As in I see, I saw? You'd better hide your sawsall. :)

3. 
   AaronRosenthal | Dec 16, 2004 09:05am | #19

   Hey, I've missed you too. Welcome back.
   18 months old, eh? It's sweet at that age.
   Be well.Quality repairs for your home.

   Aaron the HandymanVancouver, Canada

    

4. 
   Ragnar17 | Dec 16, 2004 08:51pm | #20

   Thanks for the welcome back, Aaron.  I'm surprised you guys remember me; it's been a while.

5. 
   Ragnar17 | Dec 16, 2004 09:12pm | #21

   For me, it's easier to handle the situation where the jamb is slightly proud of the rock (as opposed to the jamb being set back a tad).  For this reason, I usually make sure that the jambs are going to be at least as deep as the finished wall.  Thus, instead of adding the customary 1/16" of an inch to the calculated thickness, I'll use an 1/8". 

   When setting a window frame, I'll flush it up nicely with the interior surface and secure the frame.  Everything will now be perfect on the interior for trimming out.  When installing the exterior casings, the inboard edge can be nailed directly to the frame.  If it looks like there'll be a small gap between the outboard edge of the casing and the sheathing, then I'll add a little furring or shimming as required, and then nail off the casing.  In my opinion, a little error of a 1/16" or so is much more easily hidden on the exterior.  Especially when the "gap" is going to be hidden behind the siding anyway.

   For whatever reason, I don't ususally encounter significant problems with the actual thickness of interior walls.  As long as there's no butt seams in the rock where it hits the rough opening, there's no mud build up, and things seem to work fine.  Every once in a while, the rock requires some minor persuasion with a framing hammer and a beater block, but other than that, no problems typically.

    

   While we're on the topic of how to handle door and window trim, does anyone have any radically different ideas to address the problem at the sheetrock phase?

   I've noticed that the old plaster work seems to have been done after the jambs were set.  That way, the plaster guy could tool right against the jamb.  As a result, the finished face always came in exactly flush with the jamb. 

    

    

2. 
   HeavyDuty | Dec 15, 2004 09:11am | #6

   On the doors I just hung, (pre-hung), the jambs , which are solid 3/4" thick oak, the manufacturer put three saw cuts about 1/8" deep on the back side, so I'm guessing those are for stability?

   Those are relief cuts as the other poster mentioned. The purpose is to minimize the possibility of cupping. It depends on the grain too, if you have quartersawn and well acclimatized boards and you prime all four sides you'd probably don't need any relief cut. 

   Some milled base I've used has a wide reccessed area on the back, so I can see where that could bridge uneven spots.

   Yes that's the purpose of the slightly recessed area in case you need to scribe the trim. In your case depending on how flat the walls are and if they are finished, you may have to do that or you can put the trim on and float mud to bridge the gap.

   What I was trying to remind you was since in some places the end of the boards will be showing, if you do put in recess or relief cuts just make sure you don't go thru the ends. It happened to me more often than I want to remember.

3. 
   CapnMac | Dec 15, 2004 07:12pm | #13

   should put any cuts on the bacside and if a certain depth

   Not sure that there's any rule or formula.  I know a fella who just uses a stack dado blade with no chippers and just cuts about 1/8" deep.  Whether that does any good at all remains debatable.

   The "cup" cut on the back of base is supposed to allow a thin edge that could be scribed.  I can't recall ever seeing anybody scribe the back of base.  Doesn't mean it's never happened.

   It's probably a coin toss.  Since you are doing A&C, you'll likely be paying closer attention, which will mean a better fit.  Which almost no one but another trim man would likely notice.Occupational hazard of my occupation not being around (sorry Bubba)

4. 
   davidmeiland | Dec 15, 2004 09:47am | #10

   I almost always mill three 1/8" deep sawkerfs into the back of flat material that I'm using as trim. Obviously it depends on a lot of things--grain, moisture content and fluctuation, width, backpriming, etc.--but I think it helps prevent cupping. Set the saw fence at 1" and run a kerf from each edge. Then set the saw to the middle of the piece and run the last one.

5. 
   JerBear | Dec 15, 2004 02:51pm | #11

   David and Tom have it right.  The wider cuts are there to act as a bridge as you said.  The thin kerfs are for relief.  In woodworking this is very common in solid stock.

6. 
   hammer1 | Dec 15, 2004 05:25pm | #12

   I've just done a bunch of red oak 1x4 casings. As others have said, the sheetrock and the door and window jambs don't always meet in a perfectly even plane. A flat back board won't fit both the wall and the jamb without a plowed back. It will rock. The plow has to be set back from the jamb edge not much more than 1/2" so that it won't hit the sheetrock, just the jamb. The plow doesn't have to be very deep, 1/8" is usually plenty. I used stack dado blades on the table saw for mine. I don't bother kerfing or plowing if using flat baseboard. This last job was 1x8 with a cap molding. There was 750 lineal of base and over 2200 lf of casing, not counting extension jambs, sills and headcasings. Makes for a good pile of sawdust.

   Beat it to fit / Paint it to match

1. 
   BruceM16 | Dec 15, 2004 10:27pm | #14

   Per Hammer's description....I carry it one step further, although it is more work.

   on 1 X 4 casing with flat back, I dado out about 1 1/4 wide by 1/4" deep, centered, top to bottom. Then slide this along the wall until it contacts the jam, at the finished vertical height. Then with a VERY SHARP pencil, scribe the edge of the casing where it hits the jam...then put on a flat work top (3/4 ply clamped to sturdy horses) and hand-plane up to (but not into) the pencil line. It'll now fit over the edge of the jam and lay perfectly flat on the wall.

   When's the last time you used your Stanley 6" handplane?

   BruceM

    

1. 
   hyena | Dec 16, 2004 07:03am | #15

   Thanks guys for your tips, some excellent points and observations.

   Now let me at that wood!

2. 
   hammer1 | Dec 16, 2004 07:51am | #16

   I love my low angle block plane enough that I have four ready to go but I've learned how not to use them. What do you do when the jambs are shy of the wall? More often the case with wood framing and maybe six drywall screws. Another thing to think about with flat casing is interfering with hinges or strike plates. You sometimes have to keep the reveal stronger than with thin edge moldings. This doesn't give you much to nail to on the jamb edge. The easiest way for me is to shorten up my nails and find the angle that will get the most meat, without poking through the jamb or splitting the edge of the casing.Beat it to fit / Paint it to match

1. 
   BruceM16 | Dec 16, 2004 08:50am | #17

   Hammer

   An excellent observation, and I should have known that a sharp finish guy would pick that up in a microsecond.

   When the drywall is proud of the jam, I simply butt the casing edge up against the drywall edge from the jam side, scribe it with my razor sharp pencil, and plane it down.

   What I like about this method is that it doesn't matter (although it makes the job harder) if the wall is so out of plumb that the top of the jam is proud of the wall and then gradually as you go to the bottom, the wall is proud of the jam....you can still scribe the casing (both sides in this case) and plane to a perfect flat fit. I know, I've done it :-)

   BruceM

1. 
   jeffwoodwork | Dec 16, 2004 09:04am | #18

   For casing I think it helps to be plowed out like Hammer stated to lay flat against the walls.  I am installing knotty Alder base 1X6 and it is solid no kerfs on the back, a little tough install at places but not too bad.